|
Scientific Name | Conophytum marginatum Lavis subsp. littlewoodii (L.Bolus) S.A.Hammer |
Higher Classification | Dicotyledons |
Family | AIZOACEAE |
Synonyms | Conophytum littlewoodii L.Bolus, Conophytum marginatum Lavis var. littlewoodii (L.Bolus) Rawé |
National Status |
Status and Criteria | Endangered A3d; B1ab(iii)+2ab(iii) |
Assessment Date | 2021/11/29 |
Assessor(s) | A.J. Young, P.G. Desmet, I. Ebrahim, D. Guo, A. Harrower, L. Jabar, L. Knoetze, C. Rodgerson, P.C.V. Van Wyk & N.N. Mhlongo |
Justification | This succulent is endemic to the Karas region of Namibia and the Northern Cape province of South Africa with an extent of occurrence (EOO) of 255 km² and area of occupancy (AOO) of 24 km². It is known from only four locations and there has been observed decline in habitat quality due to the impact of droughts caused by climate change. The dwarf succulents that comprise this genus have been increasingly targeted by illegal collection in recent years and the vast majority of species are in high demand by collectors. Whilst there is no evidence of illegal collection at the time of this submission, closely related species, including other subspecies and other Conophytum species from the same area, have been illegally removed from habitat with a dramatic increase in the number of species and volume of plants targeted since 2019. The threat of illegal collection is therefore regarded as very high for this particular taxon. Its often inaccessible habit on steep cliff faces may limit the impact of collection and an overall decline to the population of between 50 and 75% is suspected over the next three generations (90 years. Climate change is also impacting the population although there is uncertainty of the response given the expected resilience of this taxon. It therefore qualifies as Endangered under criteria A3 and B1+2. |
Distribution |
Endemism | Not endemic to South Africa |
Provincial distribution | Northern Cape |
Range | This succulent is endemic to the Karas region of Namibia and the Bushmanland region of the Northern Cape province of South Africa. It is restricted to four high mountain locations, three in South Africa and one in Namibia. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Eastern Gariep Rocky Desert |
Description | This dwarf succulent is endemic to the Desert (Gariep Desert bioregion) and Nama-Karoo biomes of South Africa and Namibia, respectively. The plants occupy deeply shaded niches primarily on vertical cliff faces on quartz-rich mountains where they grow in cracks and crevices. This succulent has a generation length of 30 years. It is expected to be sensitive to the impacts of climate change as it does not disperse and while adapted to arid conditions, is dependent on limited seasonal rainfall. Species in the genus are sensitive to long periods of drought. Drought related mortality has been observed for other closely related taxa within the genus. |
Threats |
| This particular subspecies is not currently threatened by illegal collection but it is likely that it will become a target in coming years as there has been a dramatic increase in the number of species and volume of plants of this genus targeted since 2019. Other taxa, including related subspecies, within the area have experienced severe declines in population number due to illegal collection. While the small population size and limited number of locations makes the taxon highly susceptible to collection this taxon occupies remote and the often inaccessible habits (typically on cliff faces) which may limit future declines to 50-75% of the population.
Anthropogenic climate change is a long-term threat to this succulent. Loss of vegetation cover has been observed across the geographic range occupied by this succulent via Landsat imagery between 1984 and 2018 indicating a decline in habitat quality. Climate models for the likely emission scenarios where emissions stay at present day levels (RCP 2.6) (Hausfather and Peters 2020) and worst case scenarios where emissions continue to increase during the 21st century (RCP 8.5) indicate that there will be a loss of suitable bioclimatic envelope of between 39% and 85% by 2080 for this taxon. However, as this taxon occurs in a very sheltered habitat it is expected to have a level of resilience to climate change and the expected population loss is reduced by 20% to 19%. Species in this genus have limited dispersal ability and migration to suitable habitats elsewhere is regarded as highly unlikely. |
Population |
It occurs in a few high altitude subpopulations, where it is locally uncommon. The population size is difficult to estimate due to the remoteness of the area and the often inaccessible habitat occupied by the plants, often on vertical cliff faces. There is no information on population size in Namibia but in South Africa the number of plants is probably around 5,000 mature individuals. The total population is unlikely to be more than 7,500 individuals. Plants in this area have been in decline in recent years due to an extended drought and the population may be in decline.
|
Population trend | Unknown |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Conophytum marginatum Lavis subsp. littlewoodii (L.Bolus) S.A.Hammer | VU D2 | 2020.1 | | Conophytum marginatum Lavis subsp. littlewoodii (L.Bolus) S.A.Hammer | Rare | 2017.1 | | Conophytum marginatum Lavis subsp. littlewoodii (L.Bolus) S.A.Hammer | VU D2 | 2015.1 | | Conophytum marginatum Lavis subsp. littlewoodii (L.Bolus) S.A.Hammer | Rare | Raimondo et al. (2009) | |
Bibliography |
Hammer, S. 2002. Dumpling and his wife: New view of the genus Conophytum. EAE Creative Colour, Norwich.
Hammer, S.A. 1993. The genus Conophytum: A conograph. Succulent Plant Publications, Pretoria.
Hausfather, Z. and Peters, G.P. 2020. Emissions - the 'business as usual' story is misleading. Nature 577(618-620).
Opel, M.R. 2004. The rediscovery of Crassula alcicornis. Haseltonia 10:38-40.
|
Citation |
| Young, A.J., Desmet, P.G., Ebrahim, I., Guo, D., Harrower, A., Jabar, L., Knoetze, L., Rodgerson, C., Van Wyk, P.C.V. & Mhlongo, N.N. 2021. Conophytum marginatum Lavis subsp. littlewoodii (L.Bolus) S.A.Hammer. National Assessment: Red List of South African Plants version . Accessed on 2025/07/06 |
Comment on this assessment
